Satellite communications involve transmission of microwaves. Such microwaves can have small wavelengths and be transmitted at high frequencies in the gigahertz (GHz) range. Antennas can produce focused beams of high-frequency microwaves that allow for point-to-point communications having broad bandwidth and high transmission rates. A measurement that can be used to determine if an antenna is properly functioning is a microwave frequency response. This is a quantitative measure of the output spectrum of the antenna in response to a stimulus or signal. It can provide a measure of the magnitude and phase of the output of the antenna as a function of frequency in comparison to the input stimulus or signal. Determining the microwave frequency response for an antenna is a useful performance measure for the antenna.
Some antenna apertures are constructed using radio-frequency (RF) antenna segments. These apertures have thousands of RF antenna elements that form an array. Each of the antenna elements is addressed individually to generate a desired RF wave. Testing such antenna elements to identify RF antenna elements operating incorrectly is difficult when the measured response is an average response of all the RF elements in a segment unless many elements (e.g., 2-4%, 100-200 elements, etc.) are deficient.